typeof DS.attr('number')

components.my-component.js

import Ember from 'ember';

export default Ember.Component.extend({
  store: Ember.inject.service(),
  
  didInsertElement() {
    let store = this.get('store');
    let model = store.createRecord('my-model');
    this.set('model', model);
    
    model.set('age', '21');
    this.set('type', (typeof model.get('age')));
    
    console.log(model.get('age'), (typeof model.get('age')));
  }
});

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle'
});

models.my-model.js

import Model from "ember-data/model";
import attr from "ember-data/attr";
import { belongsTo, hasMany } from "ember-data/relationships";

export default Model.extend({
  age: DS.attr('number')
});

templates.application.hbs

{{my-component}}

templates.components.my-component.hbs

the age is {{model.age}} (a {{type}})

twiddle.json

{
  "version": "0.13.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.16.2",
    "ember-template-compiler": "2.16.2",
    "ember-testing": "2.16.2"
  },
  "addons": {
    "ember-data": "2.16.3"
  }
}